| REQUIREMENTS 1- This method is used for the continuous olive oil production using screw press where; - Olives that are washed and sorted, and loaded to the crushing bunker (1) are homogenously supplied to the crusher (2) and crushed at the desired size - Olives are kneaded for about an hour in the blender set (3) without adding any water or vegetative water - Olive paste is loaded through the screw conveyor (4) to one of the twin olive paste drums (6) that are mounted on the twin-piston hydraulic press (5) - As one of the twin olive paste drums (6) that are mounted on the twin piston hydraulic press (5) is filled with olive paste, pressurized and airless olive paste is loaded through outflow valves to the cold screw press of the other twin-drum (9) - Twin olive paste drums (6) are controlled by valves and the olive paste is continuously fed to the cold screw press (9) - The total pressure on the cold screw press (9) and the twin olive paste drums that are under the constant pressure of the hydraulic press leads to the separation of the olive paste into oily juice (10) and pomace - Virgin olive oil is extracted from the cold juice is obtained (10) either through settlement or centrifuge - Semi-oily juice that comes from cold press is conveyed to the hot water blender set (12) via screw conveyor (11) - The pomace is re-kneaded by adding hot water - Through the screw conveyor (13) it is fed from the hot water blender set (12) to one of the twin olive paste drums (15) that are mounted on the hydraulic press (14) - Hot screw press (16) is fed by pressurized oily pomace through outflow valves - The total pressure on the olive paste drum (15) that is under the pressure of the hydraulic press (14) and the hot screw press (16) which is under constant pressure leads to the extraction of oily juice (17) and pomace from the oily pomace - The oily juice (17) is centrifuged to give virgin olive oil. 2- For smooth operation of these stages described in Requirements 1, an 80-100 kg/cm2 pressure is required at the outflow of the screw press. |
CONTINUOUS OLIVE OIL PRODUCTION PROCESS USING SCREW PRESS
This method concerns the continuous virgin and extra-virgin olive oil production.
There are two types of olive oil production; one is discontinuous process using classical disc presses, and second production type is the continuous process by centrifuging via decanters.
In order to produce olive oil with the classical system where traditional presses are used; first, the olives are crushed and kneaded in millstone mills. The kneaded paste is then bagged and stashed in stockpiles. The oily juice that comes out of the first press is settled in settlement tanks or troughs to separate vegetative water and oil accumulates on the surface. Oil that accumulates on the surface is scraped and collected as extra virgin olive oil.
For the second press, the bags are prepared and hot water sprayed to semi-oily pomace that is left inside the bags. The bags are pressed for the second time. The juice that comes out from this second press yields virgin olive oil.
As the classical production method is labor-intensive and hard to meet hygienic requirements, producers prefer continuous production with decanter which is less labor- intensive and more hygienic.
Production using decanters yields only a single type of olive oil and water or vegetative water needed to be added to the olive paste to make it softer and more fluid for smoother decanter operation.
Olive oil that is produced by using decanters fails to provide the product with the same taste and aroma when producers get by using the classical method. Yet, it is still preferred to classical method because of being more hygienic and less labor-intensive.
In recent years, producers are inclined to leave more oil in the pomace in order to increase the quality of the oil. However, this approach causes economic losses.
This method requires that the olive paste is first cold pressed and then hot pressed to give extra-virgin and then virgin olive oil just like in the classical method. The method also ensures a continuous production process.
As it provides a continuous production process, this method also allows a less labor- intensive production under more hygienic conditions. The process ensures a control over the pressure levels in the screw press and the hydraulic press as well as the blender and kneading water temperatures. In this way, production with desired quality level can be achieved.
A detailed description of the method is as follows:
This method is employed in the continuous olive oil production and it includes the parts and machinery that are shown and numbered in Drawing 1/1. The parts and machinery used in this method are as follows:
Drawing 1: Continuous olive oil production using screw press
I- Bunker
2- Crusher
3- Blender set
4- Screw conveyor
5- Twin piston hydraulic press
6- Olive paste drums (twin)
7- Air extraction valves
8- Drum outflow valves
9- Screw press (cold press)
10- Juice outflow pipe
II- Pomace screw conveyor
12- Hot water blender set
13- Screw conveyor
14- Twin piston hydraulic press
15- Olive paste drums (twin)
16- Screw press (hot press)
17- Juice outflow pipe
Olives that are washed and de-leaved are loaded to the crushing bunker (1) where they are crushed until they reach the size which is particular for each type of olive. Crushed olives are kneaded in the blender set (3) for about an hour. In order to produce extra-virgin olive oil no water is added to the olive paste and the paste is not heated unless required otherwise.
Kneaded olive paste is loaded into one of the twin-type olive paste drums (6) by using screw conveyor (4) and pressed the hydraulic press (5). The screw conveyor (4) outflow is equipped with a valve to supply the two olive paste drums separately.
Twin piston hydraulic press (5) is designed to press the two olive paste drums independently and to sustain at the preset pressure constantly. The olive paste from the blender is first, loaded to the drum; it is then pressed by the piston that is equipped with an air extraction valve (7). The outflow valve (8) which is connected to the screw press is opened and the screw press (9) is fed under the constant preset pressure and thus the paste is pressed. While the first olive paste drum fills the screw press operation, olive paste is loaded to the second drum. As soon as the whole olive paste leaves the first drum, the outflow valve of the first drum is closed and the outflow valve (8) of the second drum is opened and the pressing process runs continuously.
In order for the screw press to press the olive paste an 80-100 kg/cm 2 pressure is required at the outflow of the screw press. This pressure is generated partly by the hydraulic press and partly by the screw press. Screw press outflow nuzzle is adjusted to sustain the required pressure levels.
The oily juice obtained at the outflow of the screw press (8) passes through the pipe (10) to the filter and then to the separation tank where it is separated from vegetative water. The product thus obtained is extra-virgin olive oil.
As neither heating nor hot water is used to attain a quality extra-virgin olive oil product in this first process, the resulting pomace is still rich with a considerable amount of oil. This remaining portion is extracted in a second set of presses using the same system above. The pomace is conveyed to the hot water filled blender (12) via the screw conveyor (11). Here, hot water is added and the blend is heated before it is re-kneaded.
The paste is then loaded through the screw conveyor (13) to one of the olive paste drums (15) of the second set of twin-piston hydraulic presses (14). As in the previous operation, it is pressed in the screw press (16) under constant pressure. The oily juice that accumulates in the pipe (17) is filtered and centrifuged to separate from the vegetative water. Hence virgin oil is obtained.
Steps described above are very similar to the classical olive oil production process. Since the entire process is completed by machines, production is more hygienic as well as efficient labor-wise.